:root {
    --bg-gradient-1: #0f172a;
    --bg-gradient-2: #312e81;
    --bg-gradient-3: #1e1b4b;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
    
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    
    --accent-color: #6366f1;
    --accent-hover: #4f46e5;
    --accent-glow: rgba(99, 102, 241, 0.5);
    
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    
    --success-color: #10b981;
    --success-hover: #059669;

    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    --font-family: 'Inter', 'Noto Sans TC', sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-family);
    background: linear-gradient(135deg, var(--bg-gradient-1), var(--bg-gradient-2), var(--bg-gradient-3));
    background-size: 400% 400%;
    animation: gradientBG 15s ease infinite;
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 2rem 1rem;
    line-height: 1.6;
}

@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.app-container {
    width: 100%;
    max-width: 900px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.app-header {
    text-align: center;
    animation: fadeInDown 0.8s ease-out;
}

.app-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    letter-spacing: -0.025em;
    background: linear-gradient(to right, #a5b4fc, #c4b5fd);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.app-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: var(--glass-shadow);
    animation: fadeInUp 0.8s ease-out;
}

.settings-panel h2, .result-panel h2 {
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 0.8rem;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.setting-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.setting-item label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

input[type="number"], select {
    width: 100%;
    padding: 0.75rem 1rem;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--glass-border);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 1rem;
    outline: none;
    transition: var(--transition);
    font-family: var(--font-family);
}

input[type="number"]:focus, select:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px var(--accent-glow);
}

select option {
    background: var(--bg-gradient-1);
    color: var(--text-primary);
}

.drop-zone {
    border: 2px dashed rgba(255, 255, 255, 0.2);
    border-radius: 16px;
    padding: 3rem 1rem;
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
    background: rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
}

.drop-zone.dragover {
    border-color: var(--accent-color);
    background: rgba(99, 102, 241, 0.1);
    transform: scale(1.02);
}

.drop-icon {
    font-size: 3rem;
    color: var(--text-secondary);
    transition: var(--transition);
}

.drop-zone:hover .drop-icon {
    color: var(--accent-color);
    transform: translateY(-5px);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-family);
}

.btn-primary {
    background: var(--accent-color);
    color: white;
}

.btn-primary:hover {
    background: var(--accent-hover);
    box-shadow: 0 0 15px var(--accent-glow);
}

.btn-danger {
    background: rgba(239, 68, 68, 0.1);
    color: #fca5a5;
    border: 1px solid rgba(239, 68, 68, 0.3);
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

.btn-danger:hover {
    background: var(--danger-hover);
    color: white;
}

.btn-generate {
    width: 100%;
    padding: 1.25rem;
    font-size: 1.25rem;
    background: linear-gradient(135deg, var(--accent-color), #8b5cf6);
    color: white;
    border-radius: 16px;
    box-shadow: 0 4px 15px var(--accent-glow);
    animation: fadeInUp 0.8s ease-out;
}

.btn-generate:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(139, 92, 246, 0.6);
}

.btn-generate:disabled {
    background: rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.3);
    cursor: not-allowed;
    box-shadow: none;
}

.btn-success {
    background: var(--success-color);
    color: white;
    text-decoration: none;
    padding: 1rem 2rem;
    font-size: 1.1rem;
    border-radius: 12px;
}

.btn-success:hover {
    background: var(--success-hover);
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.4);
}

.preview-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.thumbnail-item {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    background: rgba(255, 255, 255, 0.03);
    padding: 0.75rem;
    border-radius: 16px;
    border: 1px solid var(--glass-border);
    transition: var(--transition);
}

.thumbnail-item.dragging {
    opacity: 0.5;
    transform: scale(0.95);
    border: 1px dashed var(--accent-color);
}

.thumbnail-wrapper {
    position: relative;
    aspect-ratio: 8/9;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
    cursor: grab;
}

.thumbnail-wrapper:active {
    cursor: grabbing;
}

.thumbnail-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.thumbnail-wrapper:hover img {
    transform: scale(1.1);
}

.thumbnail-index {
    position: absolute;
    top: 5px;
    left: 5px;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    font-size: 0.75rem;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}

.thumbnail-size {
    position: absolute;
    bottom: 5px;
    left: 5px;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    font-size: 0.7rem;
    padding: 2px 6px;
    border-radius: 4px;
    backdrop-filter: blur(4px);
    pointer-events: none;
}

.thumbnail-remove {
    position: absolute;
    top: 5px;
    right: 5px;
    background: rgba(239, 68, 68, 0.8);
    color: white;
    border: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: var(--transition);
}

.thumbnail-wrapper:hover .thumbnail-remove {
    opacity: 1;
}

.thumbnail-remove:hover {
    background: var(--danger-color);
    transform: scale(1.1);
}

.thumbnail-crop {
    position: absolute;
    top: 5px;
    right: 35px;
    background: rgba(99, 102, 241, 0.8);
    color: white;
    border: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: var(--transition);
}

.thumbnail-wrapper:hover .thumbnail-crop {
    opacity: 1;
}

.thumbnail-crop:hover {
    background: var(--accent-hover);
    transform: scale(1.1);
}

.hidden {
    display: none !important;
}

.frame-controls {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.frame-text-input {
    width: 100%;
    padding: 0.6rem;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: white;
    font-size: 0.85rem;
    outline: none;
    transition: var(--transition);
}

.frame-text-input:focus {
    border-color: var(--accent-glow);
    background: rgba(0, 0, 0, 0.4);
}

.frame-settings-toggle {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 0.75rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0;
    width: fit-content;
}

.frame-settings-toggle:hover {
    color: var(--accent-color);
}

.frame-settings-panel {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.5rem;
    background: rgba(0, 0, 0, 0.2);
    padding: 0.75rem;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.05);
    animation: fadeIn 0.3s ease-out;
}

.settings-group {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.settings-group label {
    font-size: 0.7rem;
    color: var(--text-secondary);
}

.settings-group input, .settings-group select {
    padding: 0.3rem;
    font-size: 0.75rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 4px;
    color: white;
}

.btn-apply-all {
    margin-top: 0.5rem;
    padding: 0.5rem;
    background: rgba(99, 102, 241, 0.2);
    border: 1px solid var(--accent-color);
    color: white;
    border-radius: 6px;
    font-size: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
}

.btn-apply-all:hover {
    background: var(--accent-color);
}

.alignment-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-5px); }
    to { opacity: 1; transform: translateY(0); }
}

.result-display {
    display: flex;
    justify-content: center;
    align-items: center;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 1.5rem;
    border: 1px dashed var(--glass-border);
}

.result-display img {
    max-width: 100%;
    max-height: 500px;
    border-radius: 8px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

.result-actions {
    text-align: center;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.spinner {
    width: 60px;
    height: 60px;
    border: 5px solid rgba(255, 255, 255, 0.1);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s infinite linear;
    margin-bottom: 2rem;
}

.progress-bar-container {
    width: 300px;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
    margin-top: 1rem;
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--accent-color), #a855f7);
    transition: width 0.3s ease;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes scaleIn {
    from { opacity: 0; transform: scale(0.8); }
    to { opacity: 1; transform: scale(1); }
}

footer {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: auto;
    padding-top: 2rem;
    animation: fadeInUp 0.8s ease-out;
}

/* Crop Modal */
.crop-modal {
    position: fixed;
    top: 0; 
    left: 0; 
    width: 100vw; 
    height: 100vh;
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.crop-modal-content {
    width: 90%;
    max-width: 800px;
    height: 90vh;
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
}

.crop-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 1rem;
}

.btn-close {
    background: none; 
    border: none;
    color: var(--text-secondary);
    font-size: 1.5rem; 
    cursor: pointer;
    transition: var(--transition);
}

.btn-close:hover { 
    color: var(--danger-color); 
}

.crop-body {
    flex-grow: 1;
    overflow: hidden;
    background: rgba(0, 0, 0, 0.5);
    border-radius: 8px;
    margin-bottom: 1rem;
}

.img-container {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.img-container img {
    max-width: 100%;
    max-height: 100%;
    display: block;
}

.crop-footer {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
}

/* Responsive */
@media (max-width: 600px) {
    .glass-panel { padding: 1.5rem; }
    .drop-zone { padding: 2rem 1rem; }
    .app-header h1 { font-size: 2rem; }
}